powerpc/numa: Enable CONFIG_HAVE_MEMORYLESS_NODES

Based off fd1197f1 for ia64, enable CONFIG_HAVE_MEMORYLESS_NODES if
NUMA. Initialize the local memory node in start_secondary.

With this commit and the preceding to enable
CONFIG_USER_PERCPU_NUMA_NODE_ID, which is a prerequisite, in a PowerKVM
guest with the following topology:

numactl --hardware
available: 3 nodes (0-2)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46
47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94
95 96 97 98 99
node 0 size: 1998 MB
node 0 free: 521 MB
node 1 cpus: 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114
115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132
133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150
151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168
169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186
187 188 189 190 191 192 193 194 195 196 197 198 199
node 1 size: 0 MB
node 1 free: 0 MB
node 2 cpus:
node 2 size: 2039 MB
node 2 free: 1739 MB
node distances:
node   0   1   2
  0:  10  40  40
  1:  40  10  40
  2:  40  40  10

the unreclaimable slab is reduced by close to 130M:

Before:
        Slab:             418176 kB
        SReclaimable:      26624 kB
        SUnreclaim:       391552 kB

After:
        Slab:             298944 kB
        SReclaimable:      31744 kB
        SUnreclaim:       267200 kB

Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 9125964af409b641df741e775761b3394b5b69c1..bd6dd6ed3a9f1c30b4ae508057a264348b117b3f 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -457,6 +457,10 @@ config USE_PERCPU_NUMA_NODE_ID
        def_bool y
        depends on NUMA
 
+config HAVE_MEMORYLESS_NODES
+       def_bool y
+       depends on NUMA
+
 config ARCH_SELECT_MEMORY_MODEL
        def_bool y
        depends on PPC64

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index d7252adea759570911c24acc877fd4631c29973f..4863ea14f270a3de45a9ea1afa6c4023da8e3122 100644 (file)
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -755,6 +755,7 @@ void start_secondary(void *unused)
         * numa_node_id() works after this.
         */
        set_numa_node(numa_cpu_lookup_table[cpu]);
+       set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
 
        smp_wmb();
        notify_cpu_starting(cpu);